Earth’s nuclear heart

From
Chris Rosagro

A nuclear reactor at the centre of the Earth is an intriguing prospect. But I have two problems with Marvin Herndon’s hypothesis as described by Stephen Battersby (7 August, p 26).

First, the near-surface natural reactor once active at Oklo hardly supports the idea that dense uranium salts would have concentrated at the centre of the Earth. More disconcerting is the notion that gravity is a significant force near the centre of the Earth. Deep within the Earth gravitational forces cancel and the net effect is that gravity is weak within the core and zero at the Earth’s centre. …